Device for producing ammonium bicarbonate by using ammonia to capture carbon dioxide in flue gas

Abstract

The utility model relates to a device for producing ammonium bicarbonate by capturing carbon dioxide in flue gas by using ammonia, which is characterized in that ammonia is crystallized in the device to produce ammonium bicarbonate while absorbing carbon dioxide through temperature control, and ammonia escape is reduced or avoided through temperature control and zoning control.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the field of environmental protection technology, specifically relates to a device for producing ammonium bicarbonate by capturing carbon dioxide in flue gas with ammonia. BACKGROUND

[0002] Ammonium bicarbonate is a kind of quick-acting nitrogen fertilizer, and its molecular formula is NH4HCO3, which is easily dissolved in water and decomposed, and is suitable for various crops and various soils.Carbon dioxide is one of the raw materials for preparing ammonium bicarbonate, and the CO2 gas in industrial waste gas is captured and processed into ammonium bicarbonate, which not only solves the problem of CO2 directly discharged into the atmosphere, but also produces low-cost ammonium bicarbonate fertilizer.

[0003] CN101830483A discloses a production method for synthesizing ammonium bicarbonate fertilizer by using CO2 waste gas, which uses CO2 waste gas after dust removal and desulfurization to contact with concentrated ammonia water in countercurrent to generate ammonium bicarbonate, and recovers ammonia gas in the previous process through an ammonia recovery tank, and the remaining tail gas is directly discharged into the atmosphere. Although this process can produce ammonium bicarbonate by countercurrent contact absorption of concentrated ammonia water and CO2-containing gas, it only describes the basic principle of chemical reaction. Since it does not take measures to reduce the temperature and does not control the generation of ammonium bicarbonate and the absorption of CO2 from the principle, the absorption efficiency is low, ammonia escape is serious, and it does not have industrial application prospect.

[0004] CN113262625A discloses an ammonia desulfurization and decarburization integrated device and method, which uses ammonia as a desulfurization and decarburization agent. The gas first enters the desulfurization device for desulfurization to generate ammonium sulfate fertilizer. The gas after desulfurization enters the decarburization device to remove carbon dioxide in the gas to generate ammonium bicarbonate fertilizer. The gas after decarburization contains free ammonia, which is washed with desulfurization circulating liquid and then with water. The washing liquid is returned to the desulfurization tower as an absorbent for desulfurization. The process does not specifically disclose the decarburization device.

[0005] CN114870599A discloses a device and method for producing ammonium bicarbonate by ammonia decarburization system, which includes a cooling function area, an ammonium bicarbonate generation area, a carbon dioxide absorption area, and an ammonia removal function area. The cooling function area is used to remove the heat of the decarburization system, the ammonium bicarbonate generation area is used to generate ammonium bicarbonate, the carbon dioxide absorption area is used to absorb carbon dioxide in the process gas, and the ammonia removal function area is used to remove ammonia in the process gas after decarburization. The absorbent ammonia for removing carbon dioxide is mainly added from the carbon dioxide absorption area. The process does not specifically disclose the equipment and control for ammonium bicarbonate crystallization. UTILITY MODEL CONTENTS

[0006] The utility model relates to a device for producing ammonium bicarbonate by trapping carbon dioxide in flue gas with ammonia, characterized in that the device, through temperature control, makes ammonia crystallize to produce ammonium bicarbonate in the device while absorbing carbon dioxide, and reduces or avoids ammonia escape through temperature control, zoned control and washing.

[0007] A device for producing ammonium bicarbonate by trapping carbon dioxide in flue gas with ammonia, comprising a temperature adjustment zone, an ammonium bicarbonate crystallization generation zone, a carbon dioxide absorption zone and an ammonia removal zone, wherein,

[0008] The temperature adjustment zone is used for temperature adjustment of decarburized gas to meet subsequent requirements, the ammonium bicarbonate crystallization generation zone is used for generation of ammonium bicarbonate crystallization slurry, the carbon dioxide absorption zone is mainly used for absorption of carbon dioxide in flue gas, and the ammonia removal zone is used for removal of ammonia in flue gas after decarburization.

[0009] The temperature control in the utility model relates to temperature control in multiple zones, such as temperature control in the temperature adjustment zone, the ammonium bicarbonate crystallization generation zone, the carbon dioxide absorption zone and the ammonia removal zone.

[0010] The ammonium bicarbonate crystallization generation zone is provided with reaction and crystallization heat removal equipment.

[0011] Ammonium bicarbonate slurry produced by ammonium bicarbonate crystallization is sent to a post-treatment system to produce solid ammonium bicarbonate, and ammonium bicarbonate mother liquor is sent back to the decarburization device.

[0012] The temperature adjustment zone, the ammonium bicarbonate crystallization generation zone, the carbon dioxide absorption zone and the ammonia removal zone can be independently formed into towers or combined into a tower.

[0013] The ammonium bicarbonate crystallization generation zone is provided with a gas distribution device.

[0014] The ammonium bicarbonate crystallization generation zone is provided with a solid suspension device, and decarburized gas can be used for stirring. Bubble stirring can be realized through an aeration device. The aeration device is distributed in the cross section of the tower in the form of a pipe with open gas holes, the gas holes are downward or obliquely downward, and gas is bubbled downward from the gas holes.

[0015] A method for producing ammonium bicarbonate by trapping carbon dioxide in flue gas with ammonia, through temperature control, makes ammonia crystallize to produce ammonium bicarbonate in the device while absorbing carbon dioxide, and reduces or avoids ammonia escape through temperature control, zoned control and washing.

[0016] Flue gas to be decarburized is received, and the flue gas flows through the temperature adjustment zone, the ammonium bicarbonate crystallization generation zone, the carbon dioxide absorption zone and the ammonia removal zone in sequence, wherein,

[0017] The temperature adjustment zone is used to adjust the temperature of the flue gas to meet the needs of subsequent absorption and crystallization. The ammonium bicarbonate crystallization zone produces ammonium bicarbonate slurry. The carbon dioxide absorption zone is mainly used to absorb carbon dioxide in the flue gas. The ammonia removal zone is used to remove ammonia in the flue gas after decarbonization. The absorbent ammonia used to remove carbon dioxide is mainly added from the carbon dioxide absorption zone.

[0018] The ammonium bicarbonate slurry produced in the ammonium bicarbonate generation zone is sent to a post-treatment system to produce solid ammonium bicarbonate.

[0019] The carbon dioxide content in the flue gas 1 is generally not high, with a volume content of 9-35%. After pretreatment, the temperature is 40-60°C. The pretreatment generally includes denitration, dust removal, and desulfurization. The flue gas 1 passes through the cooling tower 2 to control the temperature to 15-40°C, preferably 25-40°C, such as 30-35°C. The crystallization tower 3 is equipped with a cooling device 11 to remove reaction heat and crystallization heat, and to maintain the flue gas temperature at 15-40°C, preferably 25-35°C, which is conducive to the formation of ammonium bicarbonate crystals. The carbon dioxide absorption tower 4 is controlled at a temperature of 15-40°C, or higher than the flue gas temperature of the crystallization tower 3. The carbon dioxide absorption zone is provided with at least one layer of circulating spray device and cooling device. The ammonia washing tower 5 has a flue gas outlet temperature higher than that of the absorption tower 4.

[0020] The flue gas inlet of the crystallization tower 3 is connected with the gas distribution equipment 13 and the gas bubbling stirring device 12. 60% (volume) and above of the flue gas enters the gas distribution equipment 13, and the rest enters the gas bubbling stirring device 12, which enables the flue gas to fully contact with the liquid and achieve stirring function. The gas distribution equipment 13 and the gas bubbling stirring device 12 are both arranged below the liquid level, and the gas distribution equipment 13 is located above the gas bubbling stirring device 12. The gas distribution equipment 13 is 0.2-2.5 meters away from the liquid level, which can strengthen the gas-liquid reaction and promote the formation of ammonium bicarbonate while uniformly distributing the gas. The gas bubbling stirring device 12 is 0.1-2 meters away from the tower bottom, which prevents the deposition of ammonium bicarbonate crystals. The absorbed ammonia is added to the absorption tower 4.

[0021] The temperature adjustment zone, the ammonium bicarbonate crystallization generation zone, the carbon dioxide absorption zone, and the ammonia removal zone can be combined in one tower or multiple towers, and devices / components allowing gas to pass through are provided between the zones.

[0022] The crystallization tower 3 is also provided with a stirring device 12 to prevent the deposition of ammonium bicarbonate solids. The stirring device 12 can use a side stirrer or gas bubbling stirring. The gas bubbling stirring can be achieved by an aeration device. The aeration device is a pipeline with open gas holes distributed in the cross-section of the tower. The gas holes are downward or obliquely downward, and the gas bubbles out of the gas holes and bubbles downward. When using gas bubbling stirring, the stirring gas can come from a separately set up air blower or from the flue gas treated by the cooling tower 2.

[0023] Through the above combination, the production of carbon dioxide in the ammonia capture flue gas can be controlled to produce ammonium bicarbonate, and ammonium bicarbonate crystals can be produced in the crystallization tower 3, while reducing ammonia escape.

[0024] In the design working condition, liquid ammonia is used as the absorbent to remove 80% of the CO2 in the flue gas, produce ammonium bicarbonate fertilizer, meet the requirements of GB3559-2001 standard, and the ammonia escape is less than or equal to 3 mg / Nm3.

[0025] The utility model also relates to the following implementation scheme:

[0026] 1. An apparatus for producing ammonium bicarbonate from carbon dioxide in ammonia capture flue gas, characterized in that the apparatus controls the temperature to allow ammonia to absorb carbon dioxide while crystallizing ammonium bicarbonate in the apparatus, and controls the temperature, partitions and washing to reduce or avoid ammonia escape.

[0027] 2. The apparatus of embodiment 1, wherein the partitions include a temperature adjustment zone, an ammonium bicarbonate crystallization generation zone, a carbon dioxide absorption zone, and an ammonia removal zone, and wherein,

[0028] The temperature adjustment zone is used for temperature adjustment of the decarbonized gas to meet subsequent requirements, the ammonium bicarbonate crystallization generation zone is used for generation of ammonium bicarbonate crystallization slurry, the carbon dioxide absorption zone is mainly used for absorption of carbon dioxide in the flue gas, and the ammonia removal zone is used for removal of ammonia in the flue gas after decarbonization.

[0029] 3. The apparatus of embodiment 2, wherein the ammonium bicarbonate crystallization generation zone is provided with reaction and crystallization heat removal equipment.

[0030] 4. The apparatus of embodiment 2, wherein the ammonium bicarbonate slurry produced by the ammonium bicarbonate crystallization is processed by a post-processing system to produce solid ammonium bicarbonate, and the ammonium bicarbonate mother liquor is returned to the decarbonization apparatus.

[0031] 5. The apparatus of embodiment 2, wherein the temperature adjustment zone, the ammonium bicarbonate crystallization generation zone, the carbon dioxide absorption zone, and the ammonia removal zone can be independently formed into towers or combined into a tower.

[0032] 6. The apparatus of embodiment 2, wherein the ammonium bicarbonate crystallization generation zone is provided with a gas distribution device.

[0033] 7. The apparatus of embodiment 2, wherein the ammonium bicarbonate crystallization generation zone is provided with a solid suspension device, and decarbonized gas can be used for stirring and suspension.

[0034] 8. A method for producing ammonium bicarbonate from carbon dioxide in ammonia capture flue gas, characterized in that the temperature is controlled to allow ammonia to absorb carbon dioxide while crystallizing ammonium bicarbonate in the apparatus, and the temperature, partition control and washing are controlled to reduce or avoid ammonia escape.

[0035] 9. The method of embodiment 8, comprising: receiving flue gas to be decarbonated, and passing the flue gas through, in sequence, a temperature adjustment zone, an ammonium bicarbonate crystallization generation zone, a carbon dioxide absorption zone, and an ammonia removal zone, wherein,

[0036] The temperature adjustment zone is used to adjust the temperature of the flue gas to meet the needs of subsequent absorption and crystallization, the ammonium bicarbonate crystallization generation zone generates ammonium bicarbonate slurry, the carbon dioxide absorption zone is mainly used to absorb carbon dioxide in the flue gas, and the ammonia removal zone is used to remove ammonia in the flue gas after decarbonization,

[0037] The absorbent ammonia used to remove carbon dioxide is mainly added from the carbon dioxide absorption zone.

[0038] 10. The method of embodiment 8, wherein the ammonium bicarbonate slurry generated by the ammonium bicarbonate generation zone is processed by a post-treatment system to produce solid ammonium bicarbonate.

[0039] 11. The method of embodiment 8, wherein the temperature adjustment zone adjusts the temperature of the flue gas to 15-40°C.

[0040] 12. The method of embodiment 8, wherein the ammonium bicarbonate generation zone adjusts the temperature of the flue gas to 15-40°C.

[0041] 13. The method of embodiment 8, wherein the carbon dioxide absorption zone is provided with at least one layer of circulating spray device and cooling device to adjust the temperature of the flue gas to 15-40°C. BRIEF DESCRIPTION OF DRAWINGS

[0042] Figure 1 is a schematic flow chart of the independent tower mode of the device according to some embodiments of the present disclosure.

[0043] Figure 1 The marks in each of the above-mentioned drawings have the following meanings: 1, flue gas; 2, cooling tower; 3, crystallization tower; 4, carbon dioxide absorption tower; 5, ammonia washing tower; 6, clean flue gas; 7, solid-liquid separator; 8, packaging machine; 9, solid ammonium bicarbonate; 10, ammonia; 11, cooling device; 12, stirring device; 13, gas distribution equipment. DETAILED DESCRIPTION

[0044] An exemplary embodiment of the device of the present disclosure will be described below in conjunction with the drawings.

[0045] The utility model relates to a device for producing ammonium bicarbonate by trapping carbon dioxide in flue gas with ammonia, which comprises a temperature adjustment zone, an ammonium bicarbonate crystallization zone, a carbon dioxide absorption zone and an ammonia removal zone. The temperature adjustment zone can adopt any structure suitable for temperature adjustment, and particularly comprises a cooling tower 2 and related equipment; the ammonium bicarbonate crystallization zone can adopt any structure suitable for ammonium bicarbonate crystallization, and particularly comprises a crystallization tower 3 and related equipment; the carbon dioxide absorption zone can adopt any structure suitable for carbon dioxide absorption, and particularly comprises a carbon dioxide absorption tower 4 and related equipment; and the ammonia removal zone can adopt any structure suitable for ammonia removal, and particularly comprises an ammonia washing tower 5 and related equipment.

[0046] The flue gas 1 containing CO2 after desulfurization by the ammonia method first enters the cooling tower 2. Here, the gas can be cooled by countercurrent contact with the spray liquid, which is forced to circulate by a pump and then cooled by a heat exchanger. The spray liquid can be process water, and / or a low-concentration ammonium sulfate solution in the ammonia desulfurization process, such as an ammonium sulfate solution with a concentration of ≤5% by weight, and / or a low-concentration ammonia-containing solution in the ammonia removal zone, such as an ammonia-containing solution with an ammonia content of ≤1% by weight. The spray liquid will absorb components in the flue gas 1 during circulation, such as ammonium sulfate after ammonia desulfurization.

[0047] The cooled gas enters the crystallization tower 3 through a gas distribution device 13, which is used to evenly distribute the gas across the cross-section of the device. In the crystallization tower 3, the gas is in countercurrent contact with the circulating liquid to generate ammonium bicarbonate. The flue gas leaving the crystallization tower 3 enters the carbon dioxide absorption tower 4. The solution in the crystallization tower 3 comes from the carbon dioxide absorption tower 4.

[0048] The crystallization tower 3 is also provided with a stirring device 12 to prevent the deposition of ammonium bicarbonate solids. The stirring device 12 can use a side stirrer or gas bubbling stirring. Bubbling stirring can be achieved by an aeration device. The aeration device is a pipe with open holes distributed across the cross-section of the tower, with the holes pointing downward or obliquely downward, and the gas bubbles out of the holes and bubbles downward. When using gas bubbling stirring, the stirring gas can come from a separate air blower or from the flue gas treated by the cooling tower 2.

[0049] The crystallization tower 3 is also provided with a cooling device 11 to cool the solution in the crystallization tower 3. The cooling device 11 can use a coil type.

[0050] In the carbon dioxide absorption tower 4, the gas is in countercurrent contact with the circulating liquid to generate ammonium carbonate or ammonium carbamate, and the circulating liquid is circulated by a circulating pump. Heat exchange devices can be provided on the circulating pipeline of the circulating pump.

[0051] The carbon dioxide absorption tower 4 can be a single-stage absorption or a multi-stage absorption.

[0052] Ammonia 10 is added to the carbon dioxide absorption tower 4 through a pipe.

[0053] The gas after the carbon dioxide absorption tower 4 enters the ammonia washing tower 5 for removing free ammonia in the gas. In the ammonia washing tower 5, the gas can be in countercurrent contact with water and / or an acidic solution to absorb free ammonia. The purified flue gas 6 is discharged after the removal of ammonia. The solution of the ammonia washing tower 5, in the circulation process, the components carried by the flue gas enter the circulating liquid, so that the circulating liquid contains components such as ammonium bicarbonate, a by-product of the previous ammonia method decarburization, free ammonia, etc.

[0054] The slurry of the crystallization tower 3 enters a solid-liquid separator 7 through a pump, and the obtained solid is sent to a packaging machine 8 to produce solid ammonium bicarbonate 9.

[0055] The temperature adjusting zone, the ammonium bicarbonate crystallization generating zone, the carbon dioxide absorption zone and the ammonia removal zone can be combined in one tower or multiple towers, and devices / components allowing the gas to pass are arranged between the zones.

[0056] The following embodiment 1 is provided to further illustrate the beneficial technical effects and economic effects of the device for producing ammonium bicarbonate by capturing carbon dioxide in flue gas with ammonia.

[0057] Embodiment 1

[0058] As Figure 1 A device for producing ammonium bicarbonate by capturing carbon dioxide in flue gas with ammonia, the carbon dioxide content in the flue gas 1 is 12%, and the temperature is 45-50℃. The flue gas temperature is controlled to 15-40℃, preferably 25-40℃, such as 30-35℃, by the cooling tower 2. The crystallization tower 3 is connected with a cooling device 11 for removing reaction heat and crystallization heat, and the flue gas temperature is maintained at 15-40℃, preferably 25-35℃, which is conducive to the crystallization and generation of ammonium bicarbonate. The temperature of the carbon dioxide absorption tower 4 is controlled to 15-40℃, or higher than the flue gas temperature of the crystallization tower 3. The flue gas outlet temperature of the ammonia washing tower 5 is higher than the outlet temperature of the absorption tower 4.

[0059] The flue gas inlet of the crystallization tower 3 is connected with a gas distribution device 13 and a gas bubbling stirring device 12. More than 60% (by volume) of the flue gas enters the gas distribution device 13, and the rest of the flue gas enters the gas bubbling stirring device 12, which enables the flue gas to fully contact with the liquid and achieve the stirring function. The gas distribution device 13 and the gas bubbling stirring device 12 are both arranged below the liquid level, and the gas distribution device 13 is located above the gas bubbling stirring device 12. The distance between the gas distribution device 13 and the liquid level is 0.2-2.5 meters, which can uniformly distribute the gas while strengthening the gas-liquid reaction and promoting the generation of ammonium bicarbonate. The distance between the gas bubbling stirring device 12 and the tower bottom is 0.1-2 meters, which prevents the deposition of ammonium bicarbonate crystals. The absorbed ammonia is added to the absorption tower 4.

[0060] Through the above combination, the production of ammonium bicarbonate by capturing carbon dioxide in flue gas with ammonia can be controlled, and ammonium bicarbonate crystals can be generated in the crystallization tower 3, while reducing ammonia escape.

[0061] In the design working condition, liquid ammonia is used as the absorbent to remove 80% of CO2 in the flue gas, and ammonium bicarbonate fertilizer is produced to meet the requirement of GB3559-2001 standard, and ammonia escape is less than or equal to 3 mg / Nm3.

[0062] As can be seen from the above embodiments of the present application, through temperature control, partition control and washing of the device for producing ammonium bicarbonate by capturing carbon dioxide in flue gas with ammonia, efficient decarburization and ammonia escape control can be realized, thereby achieving excellent technical and economic effects.

[0063] The above is only the preferred embodiment of the present application, and those skilled in the art can make changes according to actual needs under the guidance of the present application. Therefore, any equivalent changes and modifications made within the scope of the present application should still be within the scope of the present application.

Claims

1. An apparatus for producing ammonium bicarbonate from carbon dioxide in flue gas using ammonia, characterized in that, The device controls temperature to make ammonia crystallize into ammonium bicarbonate while absorbing carbon dioxide, and to reduce or avoid ammonia escape through temperature control, partition control and washing.

2. The apparatus for producing ammonium bicarbonate from carbon dioxide in flue gas using ammonia according to claim 1, characterized in that, The partition includes a temperature adjustment zone, an ammonium bicarbonate crystallization generation zone, a carbon dioxide absorption zone and an ammonia removal zone, wherein, The temperature adjustment zone is used for temperature adjustment of the decarburized gas to meet subsequent requirements, the ammonium bicarbonate crystallization generation zone is used for generation of ammonium bicarbonate crystallization slurry, the carbon dioxide absorption zone is mainly used for absorption of carbon dioxide in the flue gas, and the ammonia removal zone is used for removal of ammonia in the flue gas after decarburization.

3. The apparatus for producing ammonium bicarbonate from carbon dioxide in flue gas using ammonia according to claim 2, characterized in that, The ammonium bicarbonate crystallization generation zone is provided with reaction and crystallization heat removal equipment.

4. The apparatus for producing ammonium bicarbonate from carbon dioxide in flue gas using ammonia according to claim 2, characterized by, Ammonium bicarbonate slurry generated by the ammonium bicarbonate crystallization generation zone is processed by a post-processing system to produce solid ammonium bicarbonate, and ammonium bicarbonate mother liquor is returned to the decarburization device.

5. The apparatus for producing ammonium bicarbonate from carbon dioxide in flue gas using ammonia according to claim 2, characterized by, The temperature adjustment zone, the ammonium bicarbonate crystallization generation zone, the carbon dioxide absorption zone and the ammonia removal zone can be independently formed into towers or combined into a tower.

6. The apparatus for producing ammonium bicarbonate from carbon dioxide in flue gas using ammonia according to claim 2, characterized by, The ammonium bicarbonate crystallization generation zone is provided with a gas distribution device.

7. The apparatus for producing ammonium bicarbonate from carbon dioxide in flue gas using ammonia according to claim 2, characterized by, The ammonium bicarbonate crystallization generation zone is provided with a solid suspension device, and decarburized gas can be used for stirring and suspension.

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